Generally, a flat panel display device comprises a plurality of pixel units arranged in a matrix form. Pixel units are divided into two categories according to drive modes: passive matrix (referred to as PM) drive-mode pixel units and active matrix (referred to as AM) drive-mode pixel units. The AM drive-mode pixel structures have been widely applied due to obvious advantages in aspects of viewing angle, color reproduction, power consumption, response time and the like.
In a display device such as a thin film transistor liquid crystal display or an organic light-emitting diode (OLED) display, a display panel has a plurality of pixel units, the number of which is up to millions or more, and each of which comprises a thin film transistor (referred to as TFT), a storing capacitor (referred to as Cs below), a light-emitting device connected with the TFT, and the like. From the perspective of driving mechanism, an AM drive-mode pixel structure is a matrix-addressed pixel structure, which comprises gate lines (i.e. scan lines) providing row-strobe scanning signals and data lines providing column-strobe data signals to the pixel unit. The scanning signals and the data signals are acting on the TFT simultaneously, and the current of the light-emitting device connected therewith is controlled through controlling the on or off of the TFT, so that the light-emitting device can emit light within the controllable time period of one frame in order to display an image.
Taking an OLED display device as an example, as shown in FIG. 1, an 2T1C pixel circuit structure generally used in the OLED in the prior art comprises switch tubes T1 and T2 and a storing capacitor Cs. In the general OLED pixel structure, as shown in FIG. 2, each column of sub-pixel units correspond to one data line 2, and each row of sub-pixel units correspond to one scan line 3 (the scan lines in FIG. 2 are marked by dashed lines for the sake of distinguishing them from the data lines, however, in actual circuitry, the scan lines and the data lines are similar physical circuit wires; the scan lines in the following drawings are similarly marked). In a progressive scanning mode, the scan lines are enabled row by row, and the pixels are refreshed column by column. When a scan line is selected, a row strobe signal Vsel turns on T1, a data voltage Vdata charges Cs through the T1, and the voltage of Cs controls the drain current of T2. As the gate potential of the T2 gradually increasing, the T2 is turned on and stably operates in a saturation region. On the other hand, when the scan line is not selected, the T1 is cut off, charges stored on the Cs continues maintaining the gate voltage of T2, and T2 remains in a conducting state, so that the OLED is under constant-current control in a frame period.
An ultra-high-resolution display panel is featured by a large number of pixels, a large quantity of data and a high drive frequency. If the existing pixel structure connecting mode is applied to an ultra-high-resolution display device, the shortcoming of the time limitation for charging each line becomes salient; and meanwhile, the problems of a long drive wire, serious RC delay and the like also arise. Moreover, the high drive frequency will also result in an undercharge of pixel units, thereby adversely affecting display uniformity; and the long drive wire results in over-high impedance of wire in a single drive mode, thus adversely affecting the integrity of a drive signal. For example, if the total number of rows is Th and the frame refresh rate is 60 Hz in the display panel, then the charging time of each row is about 16.67 ms/Th. If the resolution is 1920*1080 and Th is 1125 in a full high definition (referred to as FHD) display panel, then the charging time of each row is about 14 μs; and if the resolution is 3840*2160 and the refresh rate is 60 Hz, then the charging time of each row is about 6 μs. It can be seen that as the resolution of the display panel increasing, the charging time is shortened greatly, and in addition, due to signal delay resulting from the wire impedance of the data lines, a predetermined charging voltage of Cs can not be reached, ultimately resulting in the shortcomings of poor display uniformity, gradual change of display brightness and the like. In a dual-gate drive mode adopted in a small-size product to increase the scanning frequency, the row charging time is only half of the original charging time, thus such drive mode can not be used in a large-size ultra-high-resolution display device either.
It is thus clear that the traditional pixel structure of the existing flat panel display device can not be applied to the ultra-high-resolution display device, and as the size of the display panel increasing, the problems comprehensively produced by the data lines and the wire impedance thereof would be more obvious, so that the problem of RC delay becomes more salient. In order to solve the above problems existing in the large-size high-resolution display device, a partitioning drive mode is often adopted at present in the technical field of display, that is, the whole display panel is partitioned into a plurality of regions (such as strip-type regions or four-quadrant regions) and to be driven respectively. In the partitioning drive mode, each region is provided with an independent source driver chip and a timing controller (TCON) chip, and utilizes a separate gate driver chip or a common gate driver. In order to adapt to the large size of the display panel, a dual-drive mode or a single-drive mode can be adopted for both the gate and the source, so as to improve the problems of insufficient driving capability and serious RC delay. However, the synchronous requirement for the timing control chip would be very high when adopting the strip-type partitioning drive mode, and difference among partitioned regions may occur during display when adopting the four-quadrant partitioning drive mode. Therefore, it is in dire need of designing a flat panel display device which is capable of not only solving the problem of undercharge of the storing capacitor Cs, but also guaranteeing the display quality.